Apparatus for insulating or covering strands and forming same into cables.



No. 699,459. Patented May 6, m2. H. w. novan. I

APPARATUS FOR INSULATING 0R COVERING STRANDS AND FORMING THE SAME INTO CABLES. Modem (Application filed Feb. 1, 1902. 2

Flo. 2.

v Arm/mar No. 699,459. Patented May 6, I902. H. w. novsn.

APPARATUS FOR INSULATING OR COVERING STRANDS AND FORMING THE SAME INTO GABLES. (No Model.) I (AppIicati m filed. Feb. 1, 1902.) 2 Sheets-Sheet 2.

inn [swim 01/ V5 r01? ##Z 1% 20mm haw ms mums ravens 0o. Pnorquma. WASHINGTON, by c.

UNITED STATES PATENT OFFICE.

HORACE XVALTER DOVER, OF NORTHAMPTON, ENGLAND.

APPARATUS FOR INSULATING 0R COVERING STRANDS AND FORMING SAME INTO CABLES.

SPECIFICATION forming part of Letters Patent No. 699,459, dated May 6, 1902.

' Application filed February 1, 1902. Serial No. 92,227. (No model.) I

To all whom it may concern:

Be it known that I, HORACE WALTER Do- VER, managing director of Dover, Limited, a subject of the King of Great Britain, residing at Park road, St. James End, Northampton, England, have invented an Improved Apparatus for Insulating or Covering Strands and Forming the Same into a Cable, of which the .followin g is a specification.

This invention relates to the manufacture of electric cables; and it consists of apparatus for covering with celluloid, xylonite, or similar material the conductors (whether plain or stranded wires) and alsowire or fibrous cords surrounding the conductor and forming the whole into a cable at one operation.

The invention will be described with reference to the accompanying drawings, forming part of this specification, wherein Figure 1 is a longitudinal sectional View, and Figs. 2 and 3 are end views, of a tool for covering and incorporating in cable form a central stranded conductor surrounded by wire or fibrous cords to impart the tensile strength required for a submarine cable, as shown in Fig. 4. Figs. 5 .and 6 show a modification, and Fig. 7 shows a cross-section, of the cable.

Referring to Fig. 1, A is the die-box, screwed to or otherwise connected with the steamjacketed pressure-chamber B of a stuffing machine or press capable of exerting a pressure of, say, one and one-fourth tons per square inch. The chamber a of the die-box is in communication with the pressure-cylin' der by an orifice Z) and terminates in a concd portion a, leading to an extrusion-nozzle a with parallel sides or very slightly coned, the diameter and length of the nozzle being such as to insure a sufficient grip of the strands by the covering material to cause the strands to be fed through along with the covering material without tension being otherwise applied to the strands. Within the chamber a project tubular guide-mandrels O O, adapted to give passage to stranded wires or cords, of which the central one is to act as the electric conductor and the outer ones to impart the necessary tensile strength to the cable. The guide-mandrels are externally tapered and converge somewhat as they approach the extrusion-nozzle a so that the intervening spaces for the passage of the insulating ma terial will be of gradually-diminishing sectional area toward the point of emergence of the strands from the tubular guide-mandrels O, which terminate in a sharp edge, soas to enable the insulating material to be delivered from the intervening passages closely around the stranded wires or cords.

' The bore of each guide-mandrel is just so much larger in diameter than the strand as to allow of the latter passing freely through it, the extrusion of the material having for efiect to cause it to drag the strand along with it without liability of the material being forced back through the bore of the guidemandrels.

In order to insure the even distribution of the material around the guide-mandrels, the

orifice 1) preferably leads into a circumfer ential channel (1, separated from the space a. by a liner-ring d, but communicating therewith by orifices d the liner having for effect to divert the material entering at b in opposite directions through the annular channel (I, whence it passes through the orifices 01 which are so graduated in diameter as to insure an equal fiow of material around the mandrels.

The tubular guide mandrels are each formed of a steel tube, the several tubes be ing mounted in a bush E, which closes the rear end of the die-box A, the guide-mandrels 0 being spaced in a circle concentrically about the central one C.

The insulating material on emerging through the spaces between the closely-juxtaposed guide-mandrels being still plastic coalesces in the form of a solid mass around and between the strands, which are thus embedded therein, so as to form a cable in which the strands are severally insulated from each other and also protected from externalinfiuences.

In Figs. 5 and 6 the outer guide-maudrels have a slight helical twist about the central guide-mandrel, so as to cause a twist to be imparted to the cable while being extruded, the nozzle a being correspondingly riftled, as shown, so as to assist in imparting the desired twist and economize insulating material by giving the cable the section shown in Fig. 7.

drel coaxial with the extrusion-nozzle and a group of similar guide-mandrels spaced in a circle around and converging toward the central guide-mandrel, all of said guide mandrels being of externally-tapered form, and leading into the die-chamber through the closed end thereof, to a point beyond the lateral inletorifices and terminating just before the coinmencement of the extrusion-nozzle, substantially as specified.

2. A die for the manufacture of electric cables by extrusion of plastic insulating material around and between a central conductive strand and a surrounding circle of strands, the said die comprising a cylindrical chamber closed at one end and having an extrusionnozzle of lesser internal diameter than that of the chamber at the other end, said chamber communicating through lateral inlet-orifices 01": graduated diameter with a circumferential channel in connection with the presscylinder for supplying the plastic material, a central tubular guide-mandrel coaxial with the extrusion-nozzle and a group of similar guide-inandrels spaced in a circle around and converging toward the central guide-mandrel, all of said guide-mandrels being of externallytapered form, and leading into the die-chamber through the closed end thereof, to a point beyond the lateral inlet-orifices and terminating just before the commencement of the extrusion-nozzle, substantially as specified.

HORACE WALTER DOVER. Witnesses:

T. W. KENNARD, J. CONWAY. 

